PMID- 16137723
OWN - NLM
STAT- MEDLINE
DCOM- 20060117
LR  - 20131121
IS  - 0028-3908 (Print)
IS  - 0028-3908 (Linking)
VI  - 49
IP  - 8
DP  - 2005 Dec
TI  - Repeated exposure to Delta(9)-tetrahydrocannabinol alters heroin-induced 
      locomotor sensitisation and Fos-immunoreactivity.
PG  - 1189-200
AB  - The present study examined the effect of chronic exposure to 
      Delta(9)-tetrahydrocannabinol (THC) on heroin-induced locomotor sensitisation and 
      Fos-immunoreactivity (Fos-IR). Adult male albino Wistar rats (n=60) were injected 
      intraperitoneally (i.p.) 21 times with vehicle, 0.05, 0.5, or 5.0mg/kg THC (once 
      every 48 h for 41 days). Locomotor activity was assessed for 180 min on 
      pre-exposure days 1, 21, and 41. Following a 2-week washout period, rats were 
      divided into five equal groups (n=12) and injected subcutaneously (s.c.) with 
      vehicle or heroin (0.5mg/kg). Locomotor activity was recorded for 240 min. In 
      drug-naive rats, heroin significantly increased locomotor activity. THC 
      pre-exposure further increased heroin-induced locomotion. After an interval of 2 
      weeks, rats pre-exposed to vehicle and 5.0mg/kg THC in the first part of the 
      experiment were randomly assigned to one of four treatment groups (n=6) and 
      injected s.c. with vehicle or 0.5mg/kg heroin and perfused 2h later. Fos-IR was 
      examined in several brain regions. Acute heroin increased Fos-IR in drug-naive 
      rats in the caudate-putamen (CPu; central, medial and dorsomedial regions), 
      nucleus accumbens (NAC; core and shell regions), bed nucleus of the stria 
      terminalis (BNST), lateral septum, central nucleus of the amygdala (CEA), 
      periaqueductal grey (PAG; dorsolateral, dorsomedial, and lateral), and the 
      Edinger-Westphal nucleus. Pre-exposure to THC significantly increased 
      heroin-induced Fos-IR in the dorsomedial CPu and the NAC (core). Conversely, THC 
      pre-exposure reduced heroin-induced Fos-IR in the BNST, CEA, and the PAG 
      (dorsolateral and lateral). The present study demonstrates that THC pre-exposure 
      increases the locomotor stimulating effects of heroin and provides new evidence 
      for the neural correlates that may underlie cannabinoid and opioid 
      cross-sensitisation.
FAU - Singh, M E
AU  - Singh ME
AD  - School of Psychology, University of New England, Armidale, NSW 2351, Australia.
FAU - McGregor, I S
AU  - McGregor IS
FAU - Mallet, P E
AU  - Mallet PE
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20050830
PL  - England
TA  - Neuropharmacology
JT  - Neuropharmacology
JID - 0236217
RN  - 0 (Hallucinogens)
RN  - 0 (Narcotics)
RN  - 70D95007SX (Heroin)
RN  - 7J8897W37S (Dronabinol)
SB  - IM
MH  - Animals
MH  - Brain/drug effects
MH  - Brain Chemistry/drug effects
MH  - Dose-Response Relationship, Drug
MH  - Dronabinol/administration & dosage/*pharmacology
MH  - Gene Expression/drug effects
MH  - Genes, fos/*genetics
MH  - Hallucinogens/administration & dosage/*pharmacology
MH  - Heroin/*pharmacology
MH  - Injections, Intraperitoneal
MH  - Injections, Subcutaneous
MH  - Male
MH  - Motor Activity/*drug effects
MH  - Narcotics/*pharmacology
MH  - Rats
MH  - Rats, Wistar
EDAT- 2005/09/03 09:00
MHDA- 2006/01/18 09:00
CRDT- 2005/09/03 09:00
PHST- 2004/12/16 00:00 [received]
PHST- 2005/07/13 00:00 [revised]
PHST- 2005/07/14 00:00 [accepted]
PHST- 2005/09/03 09:00 [pubmed]
PHST- 2006/01/18 09:00 [medline]
PHST- 2005/09/03 09:00 [entrez]
AID - S0028-3908(05)00262-5 [pii]
AID - 10.1016/j.neuropharm.2005.07.008 [doi]
PST - ppublish
SO  - Neuropharmacology. 2005 Dec;49(8):1189-200. doi: 
      10.1016/j.neuropharm.2005.07.008. Epub 2005 Aug 30.